Diagnosis and Prevention of Common Reproductive Disorder Diseases in Small and Medium-sized Pig Farms (3)
Clinical Diagnosis and Prevention of Common Reproductive Disorder Diseases in Small and Medium-scale Pig Farms (3)
The main symptoms of this disease are inflammation of the reproductive organs and fetal membranes, causing abortion, infertility, sterility and local lesions in various tissues. Sows mostly abort in the 3rd month of gestation; before abortion they show depression, reduced appetite, restlessness, swelling of the vulva and mammary glands, and reddening and edema of the vagina, with grayish-yellow or grayish-reddish-brown mucus or mucoid discharge flowing from the vagina, followed shortly by abortion, and the aborted fetuses are mostly stillborn. When boars develop orchitis, the testicles are swollen on one or both sides, hard, and hot to the touch, with testicular atrophy in the later stage. In some diseased pigs, abscesses occur in the lymph nodes of the pharynx, submandibular region, neck and groin.
The main lesions include grayish or yellowish-green flocculent fibrinous exudate on the serosa of dead fetuses, and a small amount of reddish fluid mixed with fibrin in the thoracic and abdominal cavities. The gastric contents contain yellow or white turbid mucus mixed with small floccules. Small hemorrhagic spots are seen on some mucous membranes. The placenta of aborting pigs is congested, hemorrhagic and edematous, covered with a pale yellow exudate, and in some cases necrosis is also seen. Pigs with brucellosis also commonly have arthritis, mainly affecting the larger joints of the limbs.
2.7 Porcine Chlamydiosis
Reproductive disorders in sows caused by porcine chlamydiosis mostly occur in first-parity sows, and the abortion rate of infected sows reaches 40%-90%. The clinical manifestations are sudden abortion in late pregnancy and stillbirth, with some producing stillborn piglets in the entire litter; after farrowing, sows have persistent lochia and remain infertile after multiple matings. Piglets born normally are weak and powerless, scream, shiver, have an unsteady gait, severe diarrhea, swollen joints, gradually become emaciated, and die of exhaustion. Chlamydia infection in boars manifests as orchitis, epididymitis, urethritis, balanoposthitis, etc.
The main lesions are edema and congestion of the endometrium in aborting sows, with necrotic foci of varying sizes. Aborted fetuses show edema, hemorrhage of the head, neck and limbs, and petechial hemorrhage under the skin of stillborn fetuses; the lungs are swollen with numerous hemorrhagic spots on the surface; the liver is enlarged, congested and hemorrhagic, with grayish-white spots on the surface; the kidneys are pale with petechial hemorrhage; and there are hemorrhagic patches in the intestines. In affected breeding boars, the testicles become hard, and in some cases the inguinal lymph nodes are enlarged, the vas deferens hemorrhages, and the penis is edematous, hemorrhagic or necrotic.
2.8 Porcine Toxoplasmosis
Porcine toxoplasmosis causes abortion or stillbirth in pregnant pigs; even if live piglets are born, they die acutely or are underdeveloped, unable to suckle, or are malformed fetuses, while the sow self-heals after farrowing. The mortality rate of piglets can reach 30%-40%, or even more than 60%.
Acute cases show systemic lesions, with enlargement of the lymph nodes, liver, lungs, heart and other organs, and many hemorrhagic spots and necrotic foci. The lungs are highly edematous, with widened interlobular septa filled with semitransparent gelatinous exudate; there is a large amount of mucous foam in the trachea and bronchi, and some cases are complicated by pneumonia; the systemic lymph nodes are enlarged with small necrotic spots; the liver is swollen and grayish-red, with scattered small necrotic spots; the spleen is swollen and red; the mesenteric lymph nodes are swollen in a cystic manner; there are hemorrhagic spots on the gastric fundus and patchy or band-like ulcers. Chronic cases show edema of various organs and scattered necrotic foci.
3 Prevention andControlMeasures for Porcine Reproductive Disorder Diseases
3.1 Formulate a reasonable immunization program and carry out vaccine immunization and prevention
At present there are no goodtreatmentdrugs for porcine reproductive disorder diseases, and prevention mainly relies on vaccination. Diseases with relatively severe harm, such as porcine reproductive and respiratory syndrome, porcine parvovirus disease, porcine pseudorabies, porcine circovirus disease and brucellosis, should be included in the overall immunization program of the pig farm. According to the types and epidemic characteristics of local diseases, the production characteristics of the pig farm, the age of the pigs, the characteristics of various vaccines, and the rise and fall patterns of maternal antibodies, the number of vaccinations, dosage and time intervals should be reasonably formulated. Large-scale pig farms should conduct regular antibody monitoring and promptly adjust the immunization program according to the antibody test results.